Paste supply apparatus, screen printing machine, paste supply method and screen printing method

ABSTRACT

A paste supply apparatus includes a plurality of paste pots each including a tubular container which stores paste and which includes a bottom portion provided with a through hole and a movable inner lid provided in the tubular container, and a pot holder which holds the paste pots so as to be horizontally arranged along an arrangement direction such that the through hole of each of the paste pots is directed downward and downward movement of the tubular container thereof is regulated. The paste supply apparatus further includes a pot holder moving device which moves the pot holder along the arrangement direction and selectively positions one of the plurality of paste pots at an ejection position, and a paste ejecting device which presses the inner lid of the paste pot positioned at the ejection position and which ejects the paste in the tubular container from the through hole.

BACKGROUND

1. Technical Field

An aspect of the present invention relates to a paste supply apparatus for supplying paste to a mask positioned to contact a substrate in a screen printing machine, the screen printing machine, a paste supply method and a screen printing method.

2. Background Art

As a paste supply apparatus for supplying paste to a mask positioned to contact a substrate in a screen printing machine, JP-A-2011-140176 describes an apparatus for ejecting and supplying paste to a mask from a syringe in which the paste is stored. The paste stored in the syringe is provided from a hermetically closed container called a paste pot filled with paste. The paste pot includes a tubular container and an inner lid inserted into the tubular container. JP-A-2010-172928 describes a paste supply apparatus which uses the paste pot itself as a syringe rather than refilling the syringe with paste from the paste pot.

SUMMARY

However, in the case of using the paste pot itself as the syringe as described above, paste supply cannot be continued unless the paste pot is replaced with a new paste pot when ejection of the paste in the paste pot is completed. Consequently, work efficiency decreases since operation of whole functions of the screen printing machine must be stopped in order to replace the paste pot.

An object of an aspect of the invention is to provide a paste supply apparatus, a screen printing machine, a paste supply method and a screen printing method, which can replace a paste pot without stopping operation of whole functions of the screen printing machine.

In a first aspect, a paste supply apparatus includes: a plurality of paste pots, each of which includes a tubular container which stores paste and which includes a bottom portion provided with a through hole and a movable inner lid provided in the tubular container; a pot holder which holds the plurality of paste pots so as to be horizontally arranged along an arrangement direction such that the through hole of each of the plurality of paste pots is directed downward and downward movement of the tubular container thereof is regulated; a pot holder moving device which moves the pot holder along the arrangement direction and which selectively positions one of the plurality of paste pots at an ejection position; and a paste ejecting device which presses the inner lid of the paste pot positioned at the ejection position by the pot holder moving device with respect to the tubular container and which ejects the paste stored in the tubular container from the through hole.

In a second aspect, a screen printing machine includes: a mask which is positioned to contact a substrate; a paste supply apparatus according to the first aspect, which ejects and supplies the paste to the mask contacting the substrate; and a squeegee slid on the mask to which the paste is supplied by the paste supply apparatus.

In a third aspect, a paste supply method includes: holding a plurality of paste pots, each of which includes a tubular container which stores paste and which includes a bottom portion provided with a through hole and a movable inner lid provided in the tubular container, so as to be horizontally arranged along an arrangement direction in a pot holder such that the through hole of each of the plurality of paste pots is directed downward and downward movement of the tubular container thereof is regulated; moving the pot holder in the arrangement direction and selectively positioning one of the plurality of paste pots at an ejection position; and pressing the inner lid of the paste pot positioned at the ejection position with respect to the tubular container and ejecting the paste stored in the tubular container from the through hole.

In a fourth aspect, a screen printing method includes: positioning a mask to contact a substrate; ejecting and supplying the paste from the paste supply apparatus according to the first aspect to the mask contacting the substrate; and sliding a squeegee on the mask to which the paste is supplied.

According to an aspect of the invention, after ejection of paste in one paste pot (first paste pot) is completed, another paste pot (second paste pot) is positioned at the ejection position and also the empty (first) paste pot is positioned at a position deviating from the ejection position. Consequently, the paste can subsequently be ejected from the second paste pot. Further, during that period, the empty (first) paste pot can be replaced with a new paste pot, whereby the paste pot can be replaced without stopping operation of whole functions of the apparatus (for example, the screen printing machine) which receives supply of the paste. Therefore, work efficiency can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a screen printing machine in one embodiment of the invention;

FIG. 2 is a plan view of the screen printing machine in one embodiment of the invention;

FIG. 3 is a perspective view of a squeegee unit and a paste supply apparatus provided in the screen printing machine in one embodiment of the invention;

FIG. 4A is a perspective view of the paste supply apparatus in one embodiment of the invention, and FIG. 4B is a partially sectional front view of the paste supply apparatus;

FIGS. 5A to 5C are perspective views of a paste pot used in the paste supply apparatus in one embodiment of the invention;

FIG. 6 is a block diagram showing a control system of the screen printing machine in one embodiment of the invention;

FIGS. 7A to 7C are operation explanatory diagrams of the paste supply apparatus in one embodiment of the invention;

FIGS. 8A to 8C are operation explanatory diagrams of the paste supply apparatus in one embodiment of the invention;

FIGS. 9A to 9C are operation explanatory diagrams of the paste supply apparatus in one embodiment of the invention;

FIGS. 10A to 10C are operation explanatory diagrams of the paste supply apparatus in one embodiment of the invention;

FIG. 11 is a side view of the screen printing machine in one embodiment of the invention; and

FIG. 12A is a partially sectional front view of a paste supply apparatus in a modification of one embodiment of the invention, and FIGS. 12B and 12C are side views of the paste supply apparatus.

DETAILED DESCRIPTION

An embodiment of the invention will hereinafter be described with reference to the drawings. A screen printing machine 1 shown in FIGS. 1 and 2 is a machine for repeatedly performing screen printing of paste Pst such as solder paste on a substrate 2. The screen printing machine 1 includes: a substrate holding/moving unit 4 which is provided on a base 3 and which holds and moves the substrate 2; a mask 5 horizontally disposed above the substrate holding/moving unit 4; a squeegee unit 6 provided above the mask 5; a camera unit 7 provided under the mask 5; and a paste supply apparatus 8 provided integrally with the squeegee unit 6 above the mask 5.

As shown in FIG. 1, the substrate holding/moving unit 4 includes: an XYθ movement mechanism 11 provided on the base 3; a base table 12 which is movable on a horizontal plane and rotatable around a vertical axis by the XYθ movement mechanism 11. The substrate holding/moving unit 4 further includes a first lifting table 13 and a second lifting table 14, which are provided on the base table 12 in this order from the downward side.

The XYθ movement mechanism 11 includes a stack of a Y-axis table 11 a, an X-axis table 11 b and a θ table 11 c. The Y-axis table 11 a extends in a Y-axis direction (a front-back direction viewed from an operator OP shown in FIG. 2, and the left-right direction in FIG. 1) on the base 3. The X-axis table 11 b extends along an X-axis direction (the left-right direction viewed from the operator OP, and the direction orthogonal to the sheet of FIG. 1) on the Y-axis table 11 a. The θ table 11 c is provided on the X-axis table 11 b. The X-axis table 11 b is moved on the Y-axis table 11 a along the Y-axis direction by driving of the Y-axis table 11 a, and the θ table 11 c is moved on the X-axis table 11 b along the X-axis direction by driving of the X-axis table 11 b, and the base table 12 is rotated around vertical axis (Z axis) in FIG. 1 by driving of the θ table 11 c. That is, the base table 12 is moved in the horizontal plane by an XYθ movement mechanism 11. The first lifting table 13 is moved upward and downward with respect to the base table 12 by driving of a first lifting table moving motor 13 m, and the second lifting table 14 is moved upward and downward with respect to the first lifting table 13 by driving of a second lifting table moving motor 14 m.

A pair of conveyor support members 15 is provided to extend upward from the first lifting table 13 and penetrate the second lifting table 14. The pair of conveyor support members 15 supports a pair of conveyors 16 extending in the X-axis direction. The conveyors 16 oppose each other in the Y-axis direction. The pair of conveyors 16 supports both ends of the substrate 2 from the downward side and conveys the substrate 2 in the X-axis direction. On an upper surface of the second lifting table 14, a receiving member 17 is provided.

A pair of clamp members (clampers 18) extending along the Y-axis direction and opposing each other in the X-axis direction is provided on an upper side of the pair of conveyors 16. The pair of clampers 18 is opened and closed in the Y-axis direction by actuation of a damper open/close cylinder 18 s, and grasps and holds (clamps) both ends of the substrate 2 on the conveyors 16.

As shown in FIG. 2, the mask 5 includes: a plate portion 5 a with a flat plate shape extending in an XY plane; and a frame-shaped portion 5 b for holding the outer periphery of the plate portion 5 a. An inside of a rectangular region of the plate portion 5 a surrounded by the frame-shaped portion 5 b is provided with pattern holes 5 h so as to correspond to electrodes 2 a formed on the substrate 2.

In FIG. 2, the substrate 2 includes a set of two substrate side marks 2 m at diagonal positions thereof, and the plate portion 5 a of the mask 5 includes a set of two mask side marks 5 m arranged to correspond to the substrate side marks 2 m. When the substrate 2 is positioned to contact the mask 5 in a state in which the substrate side marks 2 m overlap with the mask side marks 5 m in plan view, the electrodes 2 a of the substrate 2 become matching with the pattern holes 5 h of the mask 5.

In FIGS. 1 to 3, the squeegee unit 6 includes: a squeegee base 21 extending in the X-axis direction; two squeegees 22 which are provided below the squeegee base 21 and arranged to oppose each other in the Y-axis direction; and a squeegee unit moving mechanism 23 which moves the squeegee base 21 in the Y-axis direction. The squeegee unit moving mechanism 23 includes: a pair of squeegee unit moving ball screws 23 a which are arranged to oppose each other in the X-axis direction and extend in the Y-axis direction above the mask 5; and two squeegee unit moving motors 23 b which rotate and drive the respective squeegee unit moving ball screws 23 a. The squeegee unit moving ball screws 23 a are respectively screwed through the left and right ends of the squeegee base 21. As a result, when the squeegee unit moving ball screws 23 a are rotated forward or backward in synchronization by the two squeegee unit moving motors 23 b, the squeegee base 21 is moved along the Y-axis direction according to this rotation. The two squeegees 22 are individually moved upward and downward with respect to the squeegee base 21 by a squeegee moving cylinder 24 formed on the squeegee base 21.

In FIGS. 1 and 2, the camera unit 7 includes: an upward imaging camera 31 with an imaging visual field oriented upward; and a downward imaging camera 32 with an imaging visual field oriented downward. The camera unit 7 is moved in a horizontal plane by a camera unit moving mechanism 33.

In FIGS. 1 and 2, the paste supply apparatus 8 ejects and supplies the paste Pst to the mask 5 positioned to contact the substrate 2, and is provided on the front side of the squeegee base 21. As shown in FIG. 3, a pair of guide members 41 extending in the X-axis direction is arranged on upper and lower positions in the front of the squeegee base 21, and a ball screw 43 extending in the X-axis direction is screwed through a block member 42 guided to the pair of guide members 41. The ball screw 43 is rotatable by a paste supply apparatus moving motor 44 provided on the end of the squeegee base 21, and the block member 42 is moved in the X-axis direction by forward and backward rotation of the ball screw 43 by the paste supply apparatus moving motor 44.

As shown in FIGS. 3, 4A and 4B, the paste supply apparatus 8 includes: a base plate 51 attached to the block member 42 and extending in a vertical direction; a moving cylinder 52 made of, for example, a rod-less cylinder provided on the front of the base plate 51 so as to extend along the X-axis direction; a pot holder 54 including a base portion 81 movable along the X-axis direction on a guide 53 extending along the X-axis direction by the moving cylinder 52; and a pressing cylinder 55 provided above the pot holder 54. The pot holder 54 holds a plurality of paste pots 61 (two paste pots, in the embodiment) storing the paste Pst in a state in which the paste pots 61 are arranged along the X-axis direction.

The paste pot 61 stores the paste Pst in a tubular container 71 having a through hole 61S in a bottom portion 71 a. Before use of the paste pot 61, a cap CP attached to an open end thereof is detached (from FIG. 5A to FIG. 5B), and the paste pot 61 is changed in an attitude in which the through hole 61S is directed downward (FIG. 5C).

In FIGS. 3, 4A and 4B, the pot holder 54 includes a horizontal flat plate-shaped member, and has two pot insertion holes 54H arranged along the X-axis direction. The pot insertion holes 54H receives the paste pots 61 with the caps CP detached from above.

Each of the paste pots 61 is inserted into the corresponding pot insertion hole 54H of the pot holder 54 from above with the attitude in which the through hole 61S is directed downward. Then, each of the paste pots 61 is attached to the pot holder 54 by abutting a brim portion 71T (FIGS. 3 and 5A to 5D) formed on a side surface of the tubular container 71 on an edge portion of the pot insertion hole 54H from above. Accordingly, the two paste pots 61 are arranged and held in the horizontal direction (X-axis direction) such that the through hole 61S is directed downward and downward movement of the tubular container 71 is regulated by the pot holder 54 (FIGS. 3, 4A and 4B).

The moving cylinder 52 can move a moving body 52 a from side to side (along the X-axis direction) by supplying and draining air to and from left and right ports 52 p, thereby moving the pot holder 54 joined to the moving body 52 a from side to side. The pot holder 54 is selectively positioned at a first position (position shown in FIG. 3) or a second position by the moving cylinder 52. At the first position, the paste pot 61 inserted into the left pot insertion hole 54H is positioned at an ejection position, and the paste pot 61 inserted into the right pot insertion hole 54H is positioned at a standby position deviating from the ejection position. At the second position, the paste pot 61 inserted into the right pot insertion hole 54H is positioned at the ejection position, and the paste pot 61 inserted into the left pot insertion hole 54H is positioned at the standby position deviating from the ejection position. That is, in the embodiment, the moving cylinder 52 serves as an example of a pot holder moving device which moves the pot holder 54 along the direction (X-axis direction) in which the plurality of (two, in the embodiment) paste pots 61 are arranged, and which selectively positions one of the plurality of paste pots 61 at the ejection position. The ejection position is a position at which the paste Pst stored in the paste pot 61 is ejected. In the embodiment, the ejection position is a position at which the paste Pst can be pressed by the pressing cylinder 55. For example, the ejection position is located below the pressing cylinder 55, and the drawings of the embodiment show the ejection position located immediately below or substantially immediately below the pressing cylinder 55. The ejection position is not limited thereto as long as the paste Pst stored in the paste pot 61 can be ejected by the screen printing machine 1.

In FIGS. 3 and 4B, the pressing cylinder 55 is attached to an upper region of the base plate 51 such that a piston rod 55 a is directed downward, and a pad member 55 b is attached to a lower end of the piston rod 55 a. When the pressing cylinder 55 moves the piston rod 55 a downward to protrude, the pad member 55 b depresses an inner lid 72 of the paste pot 61 (downward movement of the tubular container 71 of the paste pot 61 is regulated as described above) positioned at the ejection position with respect to the tubular container 71, thereby applying pressure to the paste Pst stored in the tubular container 71 and ejecting the paste Pst downward from the through hole 61S.

In the embodiment, the pressing cylinder 55 serves as an example of a paste ejecting device which presses the inner lid 72 of the paste pot 61 positioned at the ejection position by the moving cylinder 52 with respect to the tubular container 71 and which ejects the paste from the through hole 61S.

The screen printing machine 1 includes a controller 100. The controller 100 controls: conveyance operation of the substrate 2 in the X-axis direction by the conveyors 16 of the substrate holding/moving unit 4; upward and downward movement operation (support operation of a lower surface of the substrate 2 described below) of the second lifting table 14 by the second lifting table moving motor 14 m; substrate clamp operation of the clampers 18 by the clamper open/close cylinder 18 s; movement operation of the substrate 2 in the horizontal plane by the XYθ movement mechanism 11; and upward and downward movement operation (upward and downward movement operation of the clamped substrate 2 described below) of the first lifting table 13 by the first lifting table moving motor 13 m (FIG. 6). The controller 100 also controls: movement operation of the squeegee unit 6 and the paste supply apparatus 8 along the Y-axis direction by the squeegee unit moving motors 23 b; movement operation of the paste supply apparatus 8 along the X-axis direction by the paste supply apparatus moving motor 44; and upward and downward movement operation of each of the squeegees 22 by the squeegee moving cylinder 24 (FIG. 6). The controller 100 also controls: movement operation of the pot holder 54 along the X-axis direction by the moving cylinder 52; and ejection operation of the paste Pst from the paste pot 61 by the pressing cylinder 55 (FIG. 6).

The controller 100 controls movement operation of the camera unit 7 in the horizontal plane by the camera unit moving mechanism 33; imaging operation of the upward imaging camera 31 provided in the camera unit 7; and imaging operation of the downward imaging camera 32 provided in the camera unit 7 (FIG. 6). The image data obtained by the imaging operation of the upward imaging camera 31 and the image data the imaging operation of the downward imaging camera 32 are inputted to the controller 100, and image recognition processing is performed in an image recognition unit 100 a (FIG. 6).

A supply procedure of the paste Pst (paste supply method) performed by the paste supply apparatus 8 will be described. At first, the operator OP inserts the two paste pots 61 into the two pot insertion holes 54H of the pot holder 54 from above (FIG. 3), respectively, so as to hold the paste pots 61 to be horizontally arranged in the pot holding part 54 such that the through holes 61S are directed downward and downward movement thereof is regulated (a pot holding step). In addition, the paste pot 61 is inserted into the pot insertion hole 54H in a state in which the pot insertion hole 54H is positioned at the standby position deviating from the ejection position.

In a state in which the two paste pots 61 are held in the pot holder 54 as described above, the controller 100 actuates the moving cylinder 52 to move the piston rod 55 a downward to protrude while the pot holder 54 is positioned at the first position (that is, the left paste pot 61 is positioned at the ejection position) (FIG. 7A; arrow A1). Accordingly, the inner lid 72 is depressed with respect to the tubular container 71 and the paste Pst is ejected downward from the through hole 61S of the left paste pot 61. Ejection of the paste Pst from the paste pot 61 is completed at the time when the inner lid 72 abuts on the bottom portion 71 a of the tubular container 71 (FIG. 7B). The completion of ejection of the paste Pst in the paste pot 61 positioned at the ejection position is detected by an ejection completion detector 55 c (FIG. 6) such as a stroke sensor which is provided inside the pressing cylinder 55 and which detects a stroke of the piston rod 55 a.

After ejection of the paste Pst from the left paste pot 61 is started, if the ejection completion detector 55 c detects completion of ejection of the paste Pst in the paste pot 61 (FIG. 7B), the controller 100 actuates the pressing cylinder 55 to move in a direction (i.e., upward direction) opposite to the direction at the time of depressing the inner lid 72 so as to position the pad member 55 b above the left paste pot 61 (FIG. 7C; arrow A2). Then, the controller 100 actuates the moving cylinder 52 so as to position the pot holder 54 at the second position, whereby the right paste pot 61 is positioned at the ejection position (FIG. 8A; arrow B1). In other words, the paste pot 61 (empty paste pot 61) having existed at the ejection position is positioned at the standby position deviating from the ejection position, and the paste pot 61 (new paste pot 61) having existed at the standby position is positioned at the ejection position. After the right paste pot 61 is positioned at the ejection position, the controller 100 moves the piston rod 55 a downward to protrude (FIG. 8B; arrow A1). Accordingly, the inner lid 72 is depressed with respect to the tubular container 71, and the paste Pst is ejected downward from the through hole 61S of the right paste pot 61 (FIG. 8B).

When or after the pot holder 54 is switched from the first position to the second position, the controller 100 actuates a notification device 101 (FIG. 6) such as a lamp connected to the controller 100 so as to provide notification that the empty paste pot 61 should be replaced with a new paste pot 61. Based on notification operation by the notification device 101, the operator OP watches for a timing when ejection operation of the paste Pst by the paste supply apparatus 8 is not performed, and at the timing, the operator OP removes the left empty paste pot 61 from the left pot insertion hole 54H (FIG. 8C; arrow C1) and then inserts the new paste pot 61 into the left pot insertion hole 54H so as to hold the new paste pot 61 in the pot holder 54 (FIG. 9A; arrow C2). The replacement work of the paste pot 61 is very easy, thereby being capable of being performed without stopping operation of whole functions of the screen printing machine 1.

After ejection of the paste Pst from the right paste pot 61 is started, if the ejection completion detector 55 c detects completion of ejection of the paste Pst in the paste pot 61 (FIG. 9B; arrow A1), the controller 100 actuates the pressing cylinder 55 in a direction (i.e., upward direction) opposite to the direction at the time of depressing the inner lid 72 so as to position the pad member 55 b above the right paste pot 61 (FIG. 9C; arrow A2). Then, the controller 100 actuates the moving cylinder 52 so as to position the left paste pot 61 at the ejection position (FIG. 10A; arrow B2). In other words, the paste pot 61 (empty paste pot 61) having existed at the ejection position is positioned at the standby position deviating from the ejection position, and the paste pot 61 (new paste pot 61) having existed at the standby position is positioned at the ejection position. After the left paste pot 61 is positioned at the ejection position, the controller 100 moves the piston rod 55 a downward to protrude (FIG. 10B; arrow A1). Accordingly, the inner lid 72 is depressed with respect to the tubular container 71, and the paste Pst is ejected downward from the left paste pot 61 (FIG. 10B).

When or after the pot holder 54 is switched from the second position to the first position, the controller 100 actuates the notification device 101 described above, and provides notification that the empty paste pot 61 should be replaced with a new paste pot 61. Based on notification operation by the notification device 101, the operator OP watches for a timing when ejection operation of the paste Pst by the paste supply apparatus 8 is not performed, and at the timing, the operator OP removes the right empty paste pot 61 from the right pot insertion hole 54H (FIG. 10C; arrow C1), and then inserts the new paste pot 61 into the right pot insertion hole 54H so as to hold the new paste pot 61 in the pot holder 54. Accordingly, since the state changes (returns) to the state of FIG. 7A described above, the paste supply operation can subsequently be continued without running out of the paste Pst.

As described above, the paste supply apparatus 8 according to the embodiment includes the ejection completion detector 55 c which detects the completion of ejection of the paste Pst in the paste pot 61 positioned at the ejection position, and if the ejection completion detector detects the completion of ejection of the paste Pst in the paste pot 61 positioned at the ejection position, the controller 100 performs control such that the paste pot 61 (empty paste pot 61) having existed at the ejection position is moved to the standby position deviating from the ejection position and the paste pot 61 (new paste pot 61) having existed at the standby position is moved to the ejection position.

Next, an execution procedure (screen printing method) of screen printing work by the screen printing machine 1 will be described. In this procedure, at first, the operator OP operates an input unit 102 (FIG. 6) connected to the controller 100 for starting a predetermined screen printing work. On receiving the input for starting the screen printing work, the controller 100 receives and conveys the substrate 2 loaded from the outside of the screen printing machine 1 by the conveyors 16, and positions the substrate 2 at a work position of below a space between the pair of clampers 18. After the second lifting table 14 is moved upward with respect to the first lifting table 13 and a lower surface of the substrate 2 is supported by the receiving member 17, the second lifting table 14 is moved further upward and the substrate 2 is lifted from the conveyors 16, and both ends of the substrate 2 are clamped and held from the Y-axis direction by a pair of clampers 18.

After the substrate 2 is clamped, the controller 100 moves the camera unit 7 to enter a space under the mask 5. The camera unit 7 images the substrate side marks 2 m provided on the substrate 2 from above the substrate 2 by the downward imaging camera 32, thereby obtaining image data of the substrate side marks 2 m. The camera unit 7 also images the mask side marks 5 m provided on the mask 5 from below the mask 5 by the upward imaging camera 31, thereby obtaining image data of the mask side marks 5 m. Then, image recognition based on the obtained image data of the substrate side marks 2 m is performed to calculate a position of the substrate 2, and image recognition based on the image data of the mask side marks 5 m is performed to calculate a position of the mask 5.

After the position of the substrate 2 and the position of the mask 5 are calculated, the controller 100 moves the camera unit 7 at a position deviating from the space under the mask 5. Then, actuation control of the XYθ movement mechanism 11 is performed to move the substrate 2 so as to position the substrate side marks 2 m under (e.g., just under) the mask side marks 5 m. Accordingly, the positioning of the substrate 2 is performed with respect to the mask 5.

After the substrate 2 is positioned with respect to the mask 5, the controller 100 moves the first lifting table 13 of the substrate holding/moving unit 4 upward with respect to the base table 12 (FIG. 11; arrow D). Accordingly, the electrodes 2 a of the substrate 2 match with the pattern holes 5 h of the mask 5, and an upper surface of the substrate 2 and upper surfaces of the clampers 18 are positioned to contact a lower surface of the mask 5 (a contact step).

After the substrate 2 is positioned to contact the mask 5, the controller 100 moves the squeegee base 21 in the Y-axis direction, and also moves the paste supply apparatus 8 in a paste supply attitude at a given or predetermined position (normally, at a position above a portion of the mask 5 which contacts the front clamper 18). Then, the paste supply apparatus moving motor 44 is actuated so as to move the paste supply apparatus 8 in the X-axis direction such that the pot holder 54 is moved in a direction (X-axis direction) in which the two paste pots 61 are arranged so as to selectively position one of the two paste pots 61 at a given or predetermined ejection position (a pot holder moving step). In this state, the inner lid 72 of the paste pot 61 positioned at the ejection position is depressed with respect to the tubular container 71, whereby the paste Pst is ejected from the through hole 61S of the paste pot 61 (an ejecting step). Accordingly, the paste Pst is supplied to the mask 5 (a paste supply step). In the paste supply step, if the notification device 101 provides the notification that the empty paste pot 61 containing no paste Pst should be replaced with a new paste pot 61, the operator OP performs replacement work of the paste pot 61 according to this notification.

After the paste Pst is supplied to the mask 5, the controller 100 moves one squeegee 22 downward with respect to the squeegee base 21 so as to abut the lower end of the squeegee 22 on the mask 5, and moves the squeegee base 21 in the Y-axis direction (FIG. 11; arrow E), whereby the squeegee 22 is slid on the mask 5 (a squeegee sliding step). Accordingly, the paste Pst supplied to the mask 5 by the paste supply step is scraped by the squeegee 22, and the paste Pst is transferred to the electrodes 2 a of the substrate 2 through the pattern holes 5 h of the mask 5.

When the paste Pst is transferred, the controller 100 abuts the front squeegee 22 (left side of paper of FIG. 11) on the mask 5 when the squeegee base 21 is moved from the front to the back of the screen printing machine 1 (from the left to the right in FIG. 11), and abuts the back squeegee 22 (right side of paper of FIG. 11) on the mask 5 when the squeegee base 21 is moved from the back to the front of the screen printing machine 1 (from the right to the left in FIG. 11).

After the transfer work of the paste Pst is completed, the controller 100 moves the first lifting table 13 downward so as to separate the substrate 2 from the mask 5. Further, holding (clamping) of the substrate 2 by a pair of clampers 18 is released, and thereafter, the second lifting table 14 is moved downward and the substrate 2 is lowered on the conveyors 16. Then, the conveyors 16 are actuated to carry the substrate 2 to the outside of the screen printing machine 1. Accordingly, the screen printing work per sheet of the substrate 2 is completed.

According to the screen printing machine 1 and the screen printing method by the screen printing machine 1 (the paste supply apparatus 8 and the paste supply method by the paste supply apparatus 8) in the embodiment as described above, after ejection of the paste Pst in one paste pot 61 (first paste pot) is completed, another paste pot 61 (second paste pot) is positioned at the ejection position and also the empty (first) paste pot 61 is positioned at the position (standby position) deviating from the ejection position. Consequently, the paste Pst can subsequently be ejected from the (second) paste pot 61. Further, during that period, the empty (first) paste pot 61 can be replaced with a new paste pot 61, whereby the paste pot 61 can be replaced without stopping operation of whole functions of the screen printing machine 1. Therefore, work efficiency can be improved.

As a modification of the above-described embodiment, the paste supply apparatus 8 may be configured to open the through hole 61 S of the paste pot 61 when the paste Pst is ejected from the paste pot 61, and close the through hole 61S of the paste pot 61 when the paste Pst is not ejected from the paste pot 61. For example, as shown in FIGS. 12A to 12C, the paste supply apparatus 8 may include: a shutter member 111 provided at a position capable of closing the through hole 61 S of the paste pot 61 positioned at the ejection position; and an operating rod 112 joined to the shutter member 111; and an operating actuator 113 provided on the lower end of the base plate 51 and configured to move the operating rod 112 along the Y-axis direction. The controller 100 operates the operating actuator 113 in conjunction with operation of the pressing cylinder 55. In this example, the controller 100 positions the shutter member 111 at an opened position of the through hole 61S when the pressing cylinder 55 is depressed (FIG. 12B), and positions the shutter member 111 at a closed position of the through hole 61S when depression of the pressing cylinder 55 is stopped (FIG. 12C). Accordingly, in a state in which the paste Pst is left inside a tubular container 71 in the paste pot 61, the paste Pst can be prevented from leakage of the through hole 61S of the paste pot 61 which may soil a supply target of the paste Pst (for example, a substrate 2) with the paste Pst.

In the embodiment described above, the pot holder 54 holds two paste pots 61 and the pot holder moving device (moving cylinder 52) selectively positions one of the two paste pots 61 at the ejection position. However, the number of paste pots 61 held by the pot holder 54 is not limited to two, and may be arbitral as long as the number of paste pots 61 is multiple (i.e., two or more).

As described above, the embodiment of the invention provides a paste supply apparatus, a screen printing machine, a paste supply method and a screen printing method, which can replace a paste pot without stopping operation of whole functions of the screen printing machine.

Although the invention has been described in detail with reference to specific embodiments, various changes or modifications may be made without departing from the spirit and scope of the invention.

This application is based on Japanese Patent Application No. 2013-123505, filed Jun. 12, 2013, the entire contents of which are incorporated herein by reference. 

What is claimed is:
 1. A paste supply apparatus comprising: a plurality of paste pots, each of which comprises a tubular container which stores paste and which comprises a bottom portion provided with a through hole and a movable inner lid provided in the tubular container; a pot holder which holds the plurality of paste pots so as to be horizontally arranged along an arrangement direction such that the through hole of each of the plurality of paste pots is directed downward and downward movement of the tubular container thereof is regulated; a pot holder moving device which moves the pot holder along the arrangement direction and which selectively positions one of the plurality of paste pots at an ejection position; and a paste ejecting device which presses the inner lid of the paste pot positioned at the ejection position by the pot holder moving device with respect to the tubular container and which ejects the paste stored in the tubular container from the through hole.
 2. A screen printing machine comprising: a mask which is positioned to contact a substrate; a paste supply apparatus according to claim 1, which ejects and supplies the paste to the mask contacting the substrate; and a squeegee slid on the mask to which the paste is supplied by the paste supply apparatus.
 3. A paste supply method comprising: holding a plurality of paste pots, each of which comprises a tubular container which stores paste and which comprises a bottom portion provided with a through hole and a movable inner lid provided in the tubular container, so as to be horizontally arranged along an arrangement direction in a pot holder such that the through hole of each of the plurality of paste pots is directed downward and downward movement of the tubular container thereof is regulated; moving the pot holder in the arrangement direction and selectively positioning one of the plurality of paste pots at an ejection position; and pressing the inner lid of the paste pot positioned at the ejection position with respect to the tubular container and ejecting the paste stored in the tubular container from the through hole.
 4. A screen printing method comprising: positioning a mask to contact a substrate; ejecting and supplying the paste from the paste supply apparatus according to claim 1 to the mask contacting the substrate; and sliding a squeegee on the mask to which the paste is supplied. 